Chemically curable liquid polyene-polythiol polymer compositions

ABSTRACT

THE INVENTION DISCLOSED IS FOR A NEW CHEMICALLY CURABLE LIQUID POLYMER COMPOSITION WHICH INCLUDES A LIQUID POLYENE COMPONENT HAVING A MOLECULAR CONTAINING AT LEAST TWO UNSATURATED CARBON-TO-CARBON BONDS DISPOSED AT TERMINAL POSITIONS ON A MAIN CHAIN BACKBONE OF THE MOLECULE, AND A POLYTHIOL COMPONENT HAVING A MOLECULE CONTAINING A MULTIPLICITY OF PENDANT OR TERMINALLY POSITIONED -SH FUNCTIONAL GROUPS PER AVERAGE MOLECULE. THE CHEMICALLY CURABLE LIQUID POLYMER COMPOSITION UPON CURING IN THE PRESENCE OF A CHEMICAL FREE RADICAL GENERATING REAGENT FORMS ODORLESS, SOLID, ELASTORMERIC PRODUCTS WHICH MAY SERVE AS SEALANTS, COATINGS, ADHESIVE, AND MOLDED ARTICLES.

United States Patent 3,662,023 CHEMICALLY CURABLE LIQUID POLYENE-POLYTHIOL POLYMER COMPOSITIONS Clifton L. Kehr, Silver Spring, andWalter R. Wszolek, Sykesville, Md., assiguors to W. R. Grace & Co., NewYork, N.Y.

No Drawing. Continuation-impart of application Ser. No. 617,801, Feb.23, 1967, which is a continuation-in-part of application Ser. No.567,841, July 26, 1966. This application June 23, 1970, Ser. No. 49,207

Int. Cl. C08g 41/04, 11/54 U.S. Cl. 260-858 26 Claims ABSTRACT OF THEDISCLOSURE The present application for US. Letters Patent is acontinuation-in-part of copending application Ser. No. 617,801, filedFeb. 23, 1967, now abandoned, which in turn is a continuation-impart ofapplication Ser. No. 567,841, filed July 26, 1966, now abandoned.

This invention relates to a new chemically curable liquid compositionwhich includes a liquid polyene component having a molecule containingat least two unsaturated carbon-to-carbon bonds disposed at terminalpositions on a main chain backbone of the molecule, a polythiolcomponent having a molecule containing a multiplicity of pendant orterminally positioned SH functional groups per average molecule, and achemical free radical generating reagent.

It is well known in the art that cure of internally unsaturated polymerssuch as polybutadiene or polyisoprene may be effected with polythiols.However, such polymers, due mainly to residual internal unsaturationafter curing, are unstable either to thermal oxidation or ultravioletcatalyzed oxidation, and are subject to rapid attack by ozone.Eventually degradation and'embrittlement result in the internal doublebond polymers, substantially reducing their useful service life.

A limitation of commercially available liquid polyurethane prepolymersis that fact that they are terminated by isocyanate (NCO) groups. TheseNCO groups are extremely unstable in storage, and are highlywater-sensitive such that under practical conditions, they react withtraces of moisture from the atmosphere to form gaseous carbon dioxideand amino groupings which in turn react \m'th more NCO to formeventually a highly viscous, sometimes completely insolubleurea-extended chain network. In cases where insolubilization occurs, thepolymer has to be discarded at great expense. Further, if theNCO-terminated prepolymers come in contact with traces of either acidicor basic impurities, dimerization and/or trimerization of the NCOfunctions may take place to form viscous, sometimes insoluble productsduring storage. Even mild alkalis such as those constituents normallypresent on the surface of glass vessels and containers may cause storageproblems.

A further limitation for some applications is found in 3,662,023Patented May 9, 1972 polyurethane polymers of the prior art which arederived from aromatic diisocyanates or polyisocyanates such astolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate, 4,4-diisocyanatodiphenylmethane, and the like. These aromatic diisocyanates(or mixtures thereof) enjoy widespread use in polyurethane elastomers,foams, and coatings, because of their ready commercial availability,high degree of reactivity and relatively low cost. The derivedpolyurethane products, however, are known to turn yellow, amber, orangeor brown in color when exposed to sunlight, ultraviolet light or otherforms of actinic radiation. This yellowing tendency imparts a definitelimitation on the usage of such polyurethanes in many applications.There is evidence in the technical literature that shows that thisyellowing or discoloration problem is directly attributable to thearomatic (benzeneoid) nucleus in the aromatic diisocyanates, andaccordingly serious yellowing problems in polyurethanes may be avoidedby use of aliphatic polyisocyanates such as hexamethylene diisocyanate.These aliphatic polyisocyanates, however, are diflicult to manufacture,are relatively expensive and are relatively slow in reaction rate duringpolymer formation reactions in comparison to the aromaticpolyisocyanates. The use of polymeric liquid polythiol polymers whichare cured to solid elastomeric products by oxidative coupling of thethiol (-SH) groups to disulfides (S-S-groups) are known in the sealants,coatings and adhesives field. Oxidizing agents such as Pb0 are commonlyused to effect this curing reaction. These mercapto-containingcompounds, however, both before and after curing with PbO -type curingsystem yield elastomeric compositions with an offensive odor whichlimits their usefulness generally to outdoor service. Thus,oxidativelycured mercapto polymer systems have found restrictedcommercial acceptance due to their offensive odors.

A limitation of commercial liquid polymeric sealants and coatings isfound in one-package systems. All the compounding ingredients, includingthe curing agents, are blended together and charged into a tightlysealed container until used. In these commercial sealants (polysulfides,polydisulfides, polymercaptans, polyurethanes and polysilicones), thecuring reaction of one-package systems is initiated by moisture (H O)from the air. The moisture-curable systems leave something to be desiredbecause the moisture content of the air varies widely. Hence, the curingperformance of moisture-curable adhesives, coatings and sealants isvariable and is difiicult to predict and control. In the case ofpolyurethanes a further disadvantage of moisture-curable systems isobserved. In the curing reaction (NCO groups reacting with H O) avolatile gas (carbon dioxide) is liberated and this evolved gas tends tocause unsightly and property-weakening gas pockets or voids in the finalproduct.

It has now been found that numerous defects of the prior art may beeffectively overcome by practice of the present invention which providesa new chemically curable liquid composition which contains particularpolyenes which are curable with polythiols to solid resins orelastomers. For example, when urethane-containing polyenes arecompounded with polythiols, the prepared composition may be storedsafely for long periods of time in the absence of a chemical freeradical generating reagent. Upon exposure to a chemical free radicalgenerating reagent, the system cures rapidly and controllably to apolythioether-polyurethane product which is low in cost and equal orbetter in reaction rate in polymer formation when compared withcompositions derived from conventional tech nology.

Generally stated, the present invention provides a cur able compositionwhich comprises a particular polyene component, a polythiol component,and a chemical free radical generating reagent.

The polyene component may be represented by the formula:

F I f -AX wherein m is an integer of at least 2, wherein X is a memberselected from the group consisting of:

In the groups (a) to (e), f is an integer from 1 to 9; R is a radicalselected from the group consisting of hydrogen, fluorine, chlorine,furyl, thienyl, pyridyl, phenyl and substituted phenyl, benzyl andsubstituted benzyl, alkyl and substituted alkyl, alkoxy and substitutedalkoxy, and cycloalkyl and substituted cycloalkyl. The substituents onthe substituted members are selected from the group consisting of nitro,chloro, fluoro, acetoxy, acetamide, phenyl, benzyl, alkyl, alkoxy andcycloalkyl. Alkyl and alkoxy have from 1 to 9 carbon atoms andcycloalkyl has from 3 to 8 carbon atoms.

The members (a) to (e) are connected to [A] through divalent chemicallycompatible derivative members. The members (a) to (e) may be connectedto [A] through a divalent chemically compatible derivative member of thegroup consisting of Si(R) carbonate, carboxylate, sulfone, O- 1 I? BC N-alkyl and substituted alkyl, cycloalkyl and substituted cycloalkyl,urethane and substituted urethane, urea and substituted urea, amide andsubstituted amide, amine and substituted amine, and aryl and substitutedaryl. The alkyl members have from 1 to 9 carbon atoms, the aryl membersare either phenyl or naphthyl, and the cycloalkl members have from 3 to8 carbon atoms with R and said members substituted being defined above.B is a member of the group consisting O-, S, and NR.

The member [A] is polyvalent; free of reactive carbonto-carbonunsaturation; free of highly water-sensitive members; and consisting ofatoms selected from the group consisting of carbon, oxygen, nitrogen,chlorine, bromine, fluorine, phosphorus, silicon and hydrogen.

The polyene component has a molecular weight in the range from about 64to 20,000, preferably about 200 to about 10,000, and a viscosity in therange from essentially 0 to 20 million centipoises at 70 C. as measuredby a Brookfield Viscometer.

The polythiol component has a molecular weight in the range from aboutto about 20,000 and the general formula:

wherein R is a polyvalent organic moiety free from reactivecarbon-to-carbon unsaturation and n is at least 2. The ene/thiol moleratio is selected so as to provide a solid, self-supporting curedproduct under ambient conditions in the presence of a free radicalgenerator.

More particularly, the member [A] of the polyene composition may beformed primarly of alkyl radicals, phenyl and urethane derivatives,oxygenated radicals, and nitrogen substituted radicals. The member [A]may also be represented by the formula:

I--POLY (ALKYLENE-ETHER) POLYOL REACTED WITH UNSATURATED MONO-l{$191215ANATES FORMIYG POLYURETHANE POLYENES AND RELATED POLY- t ill.

In the above formulas, the sum of x+y+z in each chain segment is atleast 1; P is an integer of 1 or more; q is at least 2; n is at least 1;R is selected from the group consisting of hydrogen, phenyl, benzyl,alkyl, cy cloalkyl, and substituted phenyl; and R is a member of thegroup consisting of hydrogen, phenyl, cycloalkyl, and alkyl.

The novel class of polyenes of this invention derived from carbon tocarbon unsaturated monoisocyanates may be characterized by extreme easeand versatility of manufacture when the liquid functionality desired isgreater than about three. For example, consider an attempted synthesisof a polyhexene starting with an OH terminated polyalkylene ether hexolsuch as Niax Hexol LS-490 (Union Carbide Corp.) having a molecularweight of approximately 700, and a viscosity of 18,720 cps. at 20 C. Anattempt to terminate this polymer with ene groups by reacting one moleof hexol with 6 moles of tolylene diisocyanate (mixed -2,4-, -2,6-isomerproduct) and 6 moles of allyl alcohol proceeded nicely but resulted in aprematurely chain extended and cross linked solid product rather than anintended liquid poly hexene. Using the monoisocyanate route, however,this premature chain extension may be avoided and the desiredpolyurethane-containing liquid polyhexene may be very easily prepared bya simple, one-step reaction of one mole of hexol with 6 moles of allylisocyanate. This latter polyhexene has the added advantage of beingcured using the teachings of this invention to a non-yellowingpolythioether polyurethane product. Similarly, the unsaturatedmonoisocyanate technique may be used to prepare liquid polyenes fromother analogous highly functional polyols such as cellulose, polyvinylalcohol, partially hydrolyzed polyvinyl acetate, and the like, andhighly functional polyamines such as tetraethylene pentamine,polyethyleneimine, and the like.

A general method of forming one type of polyene containing urethanegroups is to react a polyol of the general formula R {-OH) wherein R isa polyvalent organic moiety free from reactive carbon-to-carbonunsaturation and n is at least 2; with a polyisocyanate of the generalformula R {-NCO) wherein R is a polyvalent organic moiety free fromreactive carbon-to-carbon unsaturation and n is at least 2 and a memberof the group consisting of an ene-o1, yne-ol, ene-amine and yne-amine.The reaction is carried out in an inert moisture-free atmosphere(nitrogen blanket) at atmospheric pressure at a temperature in the rangefrom to about 120 C. for a period of about minutes to about hours. Inthe case where an ene-o1 or yne-ol is employed, the reaction ispreferably a one step reaction wherein all the reactants are chargedtogether. In the case where an ene-amine or yne-amine is used, thereaction is preferably a two step reaction wherein the polyol and thepolyisocyanate are reacted together and thereafter preferably at roomtemperature, the ene-amine or yne-amine is added to the NCO terminatedpolymer formed. The group consisting of ene-o1, yne-ol, ene-amine andyne-amine are usually added to the reaction in an amount such that thereis one carbon-to-carbon unsaturation in the group member per hydroxylgroup in the polyol and said polyol and group member are added incombination in a stoichiometric amount necessary to react with theisocyanate groups in the polyisocyanate.

A second general method of forming a polyene containing urethane groups(or urea groups) is to react a polyol (or polyamine) with anene-isocyanate or an yneisocyanate to form the corresponding polyene.The general procedure and stoichiometry of this synthesis route issimilar to that described for polyisocyanates in the preceding. In thisinstance, a polyol reacts with an eneisocyanate to form thecorresponding polyene. It is found, however, that products derived fromthis route, when cured in the presence of a chemical free radicalgenerating reagent and a polythiol, may form relatively weak solidpolythioether products. To obtain stronger cured products, it isdesirable to provide polar functional groupings within the main chainbackbone of the polymeric polyene. These polar functional groupingsserve as connecting linkages between multiple repeating units in themain chain series, and serve as internal strength-reinforcing agents byvirtue of their ability to create strong interchain attraction forcesbetween molecules of polymer in the final cured composition.

Polyenes containing ester groups may be formed by reacting an acid ofthe formula R {-OOOH) wherein R is a polyvalent organic moiety free fromreactive carbonto-carbon unsaturation and n is at least 2; with eitheran ene-o1 or yne-ol. The reaction is carried out in an inertmoisture-free atmosphere (nitrogen blanket) at atmospheric pressure at atemperature in the range from 0 to about C. for a period of 5 minutes to25 hours. Usually the reaction is carried out in the presence of acatalyst (p-toluene sulfonic acid) and in the presence of a solvent,e.g. benzene at refluxing temperature. The water formed is azeotroped01f of the reaction.

Another method of making an ester containing polyene is to react apolyol of the formula R {-OH), wherein R is a polyvalent organic moietyfree from reactive carbonto-carbon unsaturation and n is at least 2;with either an ene-acid or an yne-acid. The reaction is carried out inthe same manner as set out above for the ester-containing polyenes. Inpracticing this latter technique, however, it may be found thatene-acides (or yne-acids) in which the ene (or yne) group is adjacent toan activating polar moiety such as p and the like are generally notdesirable within the scope of this invention. These activated enecompounds are very prone to self-polymerization reactions to form vinylpolymers. Excessive amounts of self-polymerization of the ene groups isan undesirable side reaction in the present invention since the desiredpolythioether reaction products are precluded wheneverself-polymerization of the ene groups occurs. Finally, the presence ofactivated, easily self-polymerizable ene groups in the composition leadsto oxygen inhibition during curing, storage stability problems, or theneed for excessively high inhibitor concentrations.

In forming the urethane-containing polyenes of the present invention,catalytic amounts of a catalyst may be employed to speed up thereaction. This is especially true in the case where an ene-o1 is used toform the polyene. Such catalysts are well known to those in the art andinclude organometallic compounds such as stannous octoate, stannousoleate, dibutyl tin dilauratc, cobalt acetylacetonate, ferricacetylacetonate, lead naphthanate and dibutyl tin diacetate.

In summary, by admixing polyenes or polyynes containing two or morereactive unsaturated carbon-to-carbon bonds located terminal from themain chain with a polythiol containing two or more thiol groups permolecule and thereafter exposing said liquid mixture to a chemical freeradical generating reagent, there is provided an essentially odorlesssolid elastomeric or resinous polymeric product.

Polythiol as used herein refers to simple or complex organic compoundshaving a multiplicity of pendant or terminally positioned -SH functionalgroups per average molecule.

On the average the polythiol must contain 2 or more SH groups/moleculeand have a viscosity range of essentially to 20 million centipoises(cps.) at 70 C. as measured by a Brookfield Viscometer either alone orwhen in the presence of an inert solvent, aqueous dispersion orplasticizer. Operable polythiols in the instant invention usually havemolecular weights in the range about 50 to about 20,000 and preferablyfrom about 100 to about 10,000.

The polythiols operable in the instant invention may be exemplified bythe general formula R t-SH), where n is at least 2 and R is a polyvalentorganic moiety free from reactive carbon-to-carbon unsaturation. Thus Rmay contain cyclic groupings and hetero atoms such as N, P or O andprimarily contains carbon-carbon, carbon-hydrogen,

carbon-oxygen, or silicon-oxygen containing chain linkages free of anyreactive carbon-to-carbon unsaturation.

One class of polythiols operable with polyenes to obtain essentiallyodorless polythioether products are esters of thiol-containing acids ofthe formula HSR COOH where R is an organic moiety containing no reactivecarbon-to-carbon unsaturation with polyhydroxy compounds of structure Rtofi) where R is an organic moiety containing no reactivecarbon-to-carbon unsaturation, and n is 2 or greater. These componentswill react under suitable conditions to give a polythiol having thegeneral structure:

where R and R are organic moieties containing no reactivecarbon-to-carbon unsaturation, and n is 2 or greater.

Certain polythiols such as the aliphatic monomeric polythiols (ethanedithiol, hexamethylene dithiol, decamethylene dithiol,tolylene-2,4-dithiol, and the like, and some polymeric polythiols suchas a thiol-terminated ethylcyclohexyl dimercaptan polymer, and the like,and similar polythiols which are conveniently and ordinarily synthesizedon a commercial basis, although having obnoxious odors, are operable butmany of the end products are not widely accepted from a practical,commercial point of View. Examples of the polythiol compounds preferredbecause of relatively low odor level include but are not limited toesters of thioglycolic acid (HSCH OOOH), a-mercapto propionic acid(HS--CH(CH )COOH and fi-mercaptopropionic acid (HSCH CH COCH) withpolyhydroxy compounds such as glycols, triols, tetraols, pentaols,hexaols, and the like. Specific examples of the preferred polythiolsinclude but are not limited to ethylene glycol bis (thioglycolate),ethylene glycol bis (B-mercaptopropionate), trimethylolpropane tris(thioglycolate), trimethylolpropane tris (B-mercaptopropionate),pentaerythritol tetrakis (thio-glycolate) and pentaerythritol tetrakis(,8- mercaptopropionate), all of which are commercially available. Aspecific example of a preferred polymeric polythiol is polypropyleneether glycol bis (li-mercaptopropionate) which is prepared frompolypropylene-ether glycol (e.g. Pluracol P2010, Wyandotte ChemicalCorp.) and B-mercaptopropionic acid by esterification.

The preferred polythiol compounds are characterized by a low level ofmercaptan-like odor initially, and after reaction, give essentiallyodorless polythioether end products which are commercially attractiveand practically useful resins or elastimers for both indoor and outdoorapplications.

Prior to curing, the curable liquid polymer may be formulated for use assolids, or disposed in organic solvents, or as dispersions or emulsionsin aqueous media.

The curable liquid polymer compositions prior to curing may readily bepumped, poured, siphoned, brushed, sprayed, doctored, or otherwisehandled as desired. Following application, curing in place to a solidresin or elastomer may be effected either very rapidly or extremelyslowly as desired by manipulation of the compounding ingredients and themethod of curing.

The liquid polythioether-forming components and compositions, prior tocuring, may be admixed with or blended with other monomeric andpolymeric materials such as thermoplastic resins, elastomers orthermosetting resin monomeric or polymeric compositions. The resultingblend may be subjected to conditions for curing or cocuring of thevarious components of the blend to give cured products having unusualphysical properties.

Although the mechanism of the curing reaction is not completelyunderstood, it appears most likely that the curing reaction may beinitiated by most any chemical free radical generating reagent whichdissociates or abstracts a hydrogen atom from an SH group, oraccomplishes the equivalent thereof. Generally the rate of the curingreaction may be increased by increasing the temperature of thecomposition at the time of initiation of cure. In many applications,however, the curing is accomplished conveniently and economically byoperating at ordinary room temperature conditions. Thus for use inelastomeric sealants, it is possible merely to expose the polyene andpolythiol admixture to a chemical free radical generating reagent suchas oxygen containing gas and obtain a cured solid elastomeric orresinous product.

By proper choice of type and concentration of chemical free radicalgenerating reagent, the curing period required for conversion of thepolyene/polythiol composition from the liquid to the solid state may bevaried greatly as desired. In combination with suitable accelerators orretarders, the curing period in the presence of the various chemicalfree radical generating reagents may vary from about a few minutes orless to about 30 days or more. In general, the short curing periods areachieved in applications where thin films of curable composition arerequired, such as in the field of coatings, whereas the long curingperiods are achieved and desired where more massive layers ofcomposition are required, such as in the field of elastomeric sealants.

Chemical free radical generating reagents operable in this inventioninclude oxygen; ozone, chlorine; organic peroxides and hydroperoxides;peracids; persulfates; inorganic peroxides; and azo compounds such asazobisisovaleronitrile. Certain of these compounds may be made moreeffective and efiicient if used in conjunction with co-agent curing rateaccelerators. Examples of accelerated systems may include benzoylperoxide with dimethylaniline as an accelerator; cumene hydroperoxidewith cobalt naphthenate as an accelerator; and the like. Included inthis class are reagents or components which are generated in situ in thecomposition. Curing periods may be varied, but the reactions aregenerally relatively fast. Conversions from liquid to solid state mayoccur within a few minutes.

The chemical free radical generating reagent is usually added in anamount ranging from about 0.0005 to about 25% by weight of thephotocurable composition, with the preferred range being from about 0.05to about by weight.

Conventional curing inhibitors or retarders which may be used in orderto stabilize the components or curable compositions so as to preventpremature onset of curing may include hydroquinone; p-tert.-butylcatechol; 2,6-ditert.-butyl p methylphenol; phenothiazine; N-phenyl-2-naphthylamine; inert gas atmospheres such as helium, argon, nitrogen andcarbon dioxide; vacuum; and the like.

To obtain the maximum strength, solvent resistance, creep resistance,heat resistance and freedom from tackiness, the reaction componentsconsisting of the polyenes and polythiols of this invention areformulated in such a manner as to give solid, crosslinked, threedimensional network polythioether polymer systems on curing. In order toachieve such infinite network formation the individual polyenes andpolythiols must have a functionality of at least 2 and the sum of thefunctionalities of the polyene and polythiol components must always begreater than 4. Blends and mixtures of the polyenes and the polythiolscontaining said functionality are also operable herein.

The compositions to be cured, i.e. (converted to solid resins orelastomers) in accord with the present invention may, if desired,include such additives as antioxidants, accelerators, dyes, inhibitors,activators, fillers, pigments, anti-static agents, flame-retardantagents, thickeners, thixotropic agents, surface-active agents, viscositymodifiers, extending oils, plasticizers, tackifiers and the like withinthe scope of this invention. Such additives are usually preblended withthe polyene or polythiol prior to or during the compounding step.Operable fillers include natural and synthetic resins, carbon black,glass fibers, wood flour, clay, silica, alumina, carbonates, oxides,hydroxides, silicates, glass flakes, glass beads, borates, phosphates,diatomaceous earth, talc, kaolin, barium sulfate, calcium sulfate,calcium carbonate, antimony oxide and the like. The aforesaid additivesmay be present in quantities up to 500 parts or more per 100 partspolymer by weight and preferably about 0.005 to about 300 parts on thesame basis.

The compounding of the components prior to curing may be carried out inseveral ways. For example, the polyene, the polythiol and any otherinert additives may be admixed in an inert atmosphere and charged to anoxygen-free aerosol can, drum, tube, or cartridge for subsequent use.Exposure of admixed components to the atmosphere under ambientconditions will initiate curing. To initiate instantaneousoxygen-initiated curing, it is possible to merely admix the polyene andthe polythiol under atmospheric conditions in the absence of stabilizersor inhibitors.

The mole ratio of ene/thiol for preparing the curable composition isfrom about 0.2/1 to about 5/ 1, and desirably about 0.75/1 to about1.5/1.

The following examples will aid in explaining, but

12 should not be deemed as limiting, the instant invention. -In allcases, unless otherwise noted, all parts and percentages are by weight.

FORMATION OF POLYENE PREPOLYMER Example 1 45 8 g. (0.23 mole) of acommercially available liquid polymeric diisocyanate sold under thetradename Adiprene L- by E. I. du Pont de Nemours & Co. was charged to adry resin kettle maintained under a nitrogen atmosphere and equippedwith a condenser, stirrer, thermometer, and gas inlet and outlet. 37.8g. (0.65 mole) of allyl alcohol was charged to the kettle and thereaction was continued for 17 hours with stirring at 100 C. Thereafterthe nitrogen atmosphere was removed and the kettle was evacuated 8 hoursat 100 C. 50 cc. dry benzene was added to the kettle and the reactionproduct was azeotroped with benzene to remove the unreacted alcohol.This allyl terminated liquid prepolymer had a molecular weight ofapproximately 2100 and will be referred to as Prepolymer A hereinafter.

Example 2 400 g. (0.2 mole) of Adiprene L-100 was charged to a dry resinkettle maintained under nitrogen and equipped with a condenser, stirrer,thermometer and gas inlet and outlet. 25.2 g. (0.43 mole) of propargylalcohol (HCEG-CHzOH) was added to the kettle and the reaction wascontinued with stirring for 18 hours at 160 C. Thereafter the nitrogenatmosphere was removed and the kettle was evacuated 16 hours at 100 C.followed by azeotropic distillations with 50 cc. water and then 50 cc.benzene to remove any excess propargyl alcohol. This HCEC terminatedliquid prepolymer had a viscosity of 27,500 centipoises at 70 C. and amolecular weight of 2100 and will be referred to as Prepolymer Bhereinafter.

Example 3 1 mole of commercially available poly(ethylene ether) glycolhaving a molecular weight of 1450 and a specific gravity of 1.21 wascharged to a resin kettle maintained under nitrogen and equipped with acondenser, stirrer, thermometer and a gas inlet and outlet. 2.9 g.dibutyl tin dilaurate as a catalyst was charged to the kettle along with2 moles tolylene-2,4-diisocyanate and 2 moles of allyl alcohol. Thereaction was continued with stirring at 60 C. for 2 hours. Thereafter avacuum of 1 mm. was applied for 2 hours at 60" C. to remove the excessalcohol. This CH =CH- terminated prepolymer had a molecular weight ofapproximately 1950 and will hereinafter be referred to as Prepolymer C.

Example 4 1 mole of a commercially available poly(propylene ether)glycol having a molecular weight of about 1958 and a hydroxyl number of57.6 was charged to a resin kettle equipped with a condenser, stirrer,thermometer and a gas inlet and outlet. 4 g. of dibutyl tin dilurate asa catalyst was added to the kettle along with 348 g. (2.0 moles) oftolylene-2,4-diisocyanate and 116 g. (2 moles) of allyl alcohol. Thereaction was carried out for 20 minutes at room temperature undernitrogen. Excess alcohol was stripped from the reaction kettle by vacuumover a 1 hour period. The thus formed CH =CH- terminated liquidprepolymer had a molecular weight of approximately 12400 and willhereinafter be referred to as Prepolymer D.

Example 5 750 g. of a N-containing tetrol (hydroxyl functionality=4)available from Wyandotte Chemicals Corp. under the tradename TetronicPolyol 904 having a M.W. of 7,500 was placed in a reaction vessel heatedat C. The flask was maintained under vacuum for 1 hour. Then, under anatmosphere of nitrogen, 0.1 cc. dibutyl tin dilaurate was added and theflask was cooled to 50 C. Now 18.3 g. allyl isocyanate was added slowly,maintaining the temperature at about 95 C. for about 1 hour after theaddition was completed. The thus formed polymeric polyene (i.e.,Prepolymer E hereinafter) had a theoretical allyl functionality of 2.2,a theoretical hydroxyl functionality of 1.8, and a calculated molecularweight of about 7,683.

Example 6 To a resin kettle maintained under a nitrogen atmosphere andequipped with a condenser, stirrer, thermometer and gas inlet and outletwas added 843 g. of a commercially available liquid diisocyanateprepolymer sold under the tradename Multrathane F-196 by Mobay ChemicalCo., said prepolymer having a molecular weight of about 1680 and anavailable isocyanate content of 4.75.2%. 87 g. (1.5 moles) of allylalcohol was added to the kettle and the reaction was continued for v18hours at 140 C. with stirring. Thereafter the nitrogen atmosphere wasremoved and the kettle was evacuated for 22 hours at 100 C. 50 cc. ofdry benzene was added to the kettle and the reaction product wasazeotroped therewith to remove any unreacted alcohol. This CH =CH-terminated liquid prepolymer had a viscosity of 25,000 centipoises at 70C. and a molecular weight of approximately 1800 and will be referred toas Prepolymer F hereinafter.

Example 7 678 g. (0.34 mole) of a commercially available poly-(propylene ether) glycol sold under the trade name NIAX by Union CarbideCo. and having a molecular weight of about 2025 was degassed for 2 hoursat 100 C. and thereafter charged to a resin kettle maintained under anitrogen atmosphere and equipped with a condenser, stirrer, thermometerand gas inlet and outlet. 118 g. (0.68 mole) of tolylene2,4-diisocyanate was charged to the kettle and the reaction was heatedwith stirring for 2% hours at 120 C. After cooling, 5.8 g. (1.0 mole) ofallyl alcohol was added to the kettle and the mixture Was refluxed at120 C. for 16 hours under nitrogen. Excess allyl alcohol was removedovernight by vacuum at 100 C. Half of the allyl terminated liquidprepolymer having a viscosity of 19,400 cps. at 30 C. as measured on aBrookfield Viscometer was removed from the kettle and will be referredto hereinafter as Prepolymer G. The other half portion of the prepolymerwas combined with 50 cc. of dry benzene and azeotroped overnightfollowing which excess benzene was pulled out under vacuum for hours at120 C. This portion of the allyl-terminated liquid prepolymer had aviscosity of 15,600 cps. at 70 C. as measured on a Brookfield Viscometerand a molecular weight of approximately 2500 and will hereinafter bereferred to as Prepolymer H.

Example 8 751 g. (0.38 mole) of a commercially available poly-(propylene ether) glycol sold under the trade name Pluracol P 2010" byWyandotte Chemical Co. was degassed at room temperature for 3 hours andthen charged to a dry resin kettle maintained under a nitrogenatmosphere and equipped with a condenser, stirrer, thermometer and gasinlet and outlet. 132 g. (0.76 mole) of tolylene-2,4- diisocyanate wascharged to the kettle and the kettle was heated for 2 hours at 120 C.with stirring under nitrogen. After cooling 58 g. (1.0 mole) of allylalcohol was added and the mixture was refluxed at 120 C. overnight.Excess allyl alcohol was stripped by vacuum overnight at 120 C. The thusformed allyl terminated liquid prepolymer had a viscosity of 15,000 cps.as measured on a Brookfield Viscometer at 70 C. and a molecular weightof approximately 2500 and will hereinafter be referred to as PrepolymerI.

Example 9 To a 1 liter resin kettle equipped with stirrer, thermometer,gas inlet and outlet and heated to a temperature of 50 C. was charged610 g. (0.2 mole) of poly(tetramethylene ether) glycol, commerciallyavailable from Quaker Oats Co. and having a hydrozyl number of 37.1along with 0.3 g. dibutyl tin dilaurate. The temperature of the kettlewas raised to C. and the contents were freed of water under 1 millimetervacuum for 1 hour. The resin kettle was cooled to 60 C. and the systemwas placed under a protective atmosphere of nitrogen throughout theremainder of the reaction. 25.2 g. of allyl isocyanate (0.4 mole) wasadded dropwise to the kettle as such a rate as to maintain thetemperature at 60 C. When the NCO content dropped to 0.54 mg./g., 1 mm.vacuum again was applied and the system was heated at 70 C. for onehour. The thus formed polymer product was a solid at room temperaturebut at 50 C. is clear and pourable. The polymer product had a viscosityof 1,800 centipoises at 70 C. as measured on a Brookfield Viscometer andan average molecular weight of approximately 3200.

Example 10 i To a 1 liter resin kettle equipped with stirrer,thermometer, gas inlet and outlet was charged 591 g. (0.30 mole) ofpoly(propylene ether) glycol commercially available from Union Carbideunder the trade name PPG 2025 and 0.3 g. of dibutyl tin dilaurate. Thekettle was heated to 110 C. and the contents were freed of water under 1mm. vacuum for 1 hour. The kettle was cooled to 25 C. and the system wasplaced under a protective atmosphere of nitrogen throughout theremainder of the reaction. 53.1 ml. (49.8 g., 0.6 mole) of allylisocyanate commercially available from Chemetron Corp. was added to thesystem. An exotherm carried the temperature to 45 C. in 22 minutes.After 60 minutes, the NCO content (as determined by tritration) was 0.04mg./g. The system was placed under 1 mm. vacuum and heated to 70 C. toremove traces of unreacted allyl isocyanate. The resultant polymerproduct had a viscosity of 600 centipoises at 30 C. as measured on aBrookfield Viscometer and an average molecular weight of approximately2200.

The next two examples show a method of preparing the polyenes of theinstant invention by dehydration of polyether glycols.

Example 11 100 g. of poly(propylene ether) glycol commercially availablefrom Union Carbide under the trade name PPG 2025 was poured through ahot tube filled with aluminum oxide at such a rate that the entirereaction took place in 2 hours. The tube was 1" in diameter with thereaction zone 1 ft. long and completely enclosed within a tube furnace.The alumina catalyst was 10-18 mesh and was maintained at 350 C. using aLindberg Hevi-Duty tube furnace. The tube was fitted with a droppingfunnel and a nitrogen inlet at the top. Nitrogen pressure was kept onthe system throughout the reaction. The product collected from thebottom of the tube was analyzed for unsaturation by the mercuric acetatetitration method and was found to have 100% of the theoretical amount ofunsaturation expected after dehydration of both terminal hydroxyl groupsof the poly(propylene ether) glycol. The polyene product had a viscosityof cps. at 70 C. and an average molecular weight of approximately 2000.

Example 12 1 kilogram of poly(propylene ether) glycol commerciallyavailable from Union Carbide under the trade name PPG 2025 was heated to120 C. in a round bottom flask. To this was added 120 ml. (20% excess)of acetic anhydride at such a rate that the temperature of the mixturewas kept at 120-140 C. Following the addition, the mixture was heated atC. for 4 hours. It was then cooled and diluted with an equal volume ofchloroform, washed with aqueous sodium carbonate, then with water. Theorganic layer was separated and the chloroform was removed bydistillation. Infrared analysis of the purified material showed it to bethe diacetate of the poly(propylene ether) glycol with no resid alhydroxyl groups.

100 g. of this diacetate was put through the hot tube as in Example 11except that the packing was glass helices instead of alumina and thetemperature was 375 C. The product contained 64% of the theoreticalamount of unsaturation expected after the elimination of acetic acidfrom both terminal acetoxy groups of the poly(propyl ene ether) glycoldiacetate.

Example 13 114 g. of hexol sold under the trade name NIAX Polyol LS490by Union Carbide Chemical Co. having a molecular weight of 684 wascharged to a 1 liter 4 neck flash and heated to 110 C. under vacuum andnitrogen for 1 hour. It was then cooled to approximately 60 C. whereat0.1 cc. of dibutyl tin dilaurate was added followed by slowly adding 83g. (1 mole) of allyl isocyanate continue for 1 hour at 70 C. Thepolymeric hexane the addition. After addition, the reaction was allowedto continue for 1 hour at 70 C. The polymeric hexaene product obtainedhad an average molecular weight of approximately 1200 and a viscosity of300 centipoises at 70 C.

Example (14 To a 1 liter 4 neck flask was charged 300 milliliters ofdimethylformamide, 35 g. of tolylene-2,4-diisocyanate and 0.1 cc. ofdibutyl tin dilaurate. A mixture of 11.6 g. of allyl alcohol and 22.8 g.of hexol commercially available irom Union Carbide Chemical Co. underthe trade name NIAX Polyol LS-490 having a molecular weight of 684 wasslowly added to the flask. Temperature was kept at approximately 65 C.during the addition and for a period of 1 hour. The polymeric productobtained had an average molecular weight of approximately 2100.

Example 15 To a !1 liter 4 neck flask was charged 100 cc. ofdimethylformamide, 100 g. of tolylene-2,4-diisocyanate and 0.1 cc.dibutyl tin dilaurate. '58 g. of hexol, i.e. NIAX Polyol IJS-490 byUnion Carbide and 34 g. of allyl alcohol were mixed together and addeddropwise to the flask. Before the addition to the flask was completed,the reaction, which was exothermic, gelled and the addition wasdiscontinued.

A comparison of Examples 13, 14 and 15 shows that Example 13 is animprovement over Examples 14 and 15 in that it allows one to formpolymer Without the necessity of a solvent. A comparison of Examples 14and 15 shows that when starting with a highly functional polyol usingthe diisocyanate/allyl alcohol technique one must operate in dilutesolution to avoid premature cros'slinking (i.e., gelation) which rendersthe polyene product useless as a curable liquid prepolymer. This problemis avoided completely by using the unsaturated monoisocyanate techniqueillustrated in Example 13.

1 6 Example 16 In a !1 liter, 4 neck flask 220 g. of hexol commerciallyavailable from Union Carbide Chemicals Co. under the tradename NIAXPolyol LS-490 (0.32 mole) and 0.1 cc. of dibutyl tin dilaurate washeated to 110 C. under vacuum for 1 hour. After cooling in nitrogen toapproximately C., g. of allyl isocyanate was added to the flask by meansof a dropping funnel. The exothermic reaction produced a temperature ofC. When the addition was complete the reaction was continued at 70 C.for 1 hour. The resulting triene polymer product had an averagemolecular weight of approximately 950 and a viscosity of 300 centipoisesas measured on a Brookfield Viscometer at 70 C.

Example 17 To a 1 liter 4 neck flask was charged 300 g. of a polyesterdiol (molecular weight 3232.) sold under the trade name RC Polyester S101-35 by R. C. Division, Hooker Chemical Corp. and 0.1 cc. of dibutyltin dilaurate. The flask was heated to C. of dibutyl tin dilaurate. Theflask was heated to 1 10 C. under vacuum and maintained thereat for 1hour. The flask was cooled to approximately 60 C., nitrogen wasadmitted, and 7.7 g. allyl isocyanate and 8.1 g. oftolylene-Z,4-diisocyanate was added by means of a dropping funnel to thereaction at a moderate rate. A maximum temperature of 90 C. was needed.When the addition was complete the reaction was allowed to continue at70 C. for 1 hour. The thus formed solid polymeric product had an averagemolecular weight of approximately 6800 and a viscosity of 13,600centipoises when measured on a Brookfield Viscometer at 70 C.

Example 18 To a 1 liter 4 neck flask heated at 110 C. was charged 808 g.of a polyester diol (having a molecular weight 3232) sold under thetrade name RC Polyester S 101- 35 by R. C. Division Hooker ChemicalCorp. and 0.1 cc. dibutyl tin dilaurate. The flask was maintained undervacuum at 110 C. for :1 hour. The flask was cooled to approximately 50C. and with nitrogen passing through, a mixture of 10 g. of allylalcohol and 60 g. of tolylene- '2,4 diisocyanate was added via adropping funnel at a moderate rate. The reaction was allowed to continuefor 15 minutes. A maximum temperature of 90 C. was produced by theexothermic reaction. The polymeric product obtained was a solid at roomtemperature but liquid at 70 C. The product had an average molecularweight of approximately 10,500 and a viscosity of 270,000 centipoises at70 C.

Example 19 Following the procedure of Example 12 and using necessaryreactants, a polyene of the following formula was prepared:

Example 20 Following the procedure of Example 3, and using necessaryreactants, a polyene of the following formula was prepared:

17 18 Example 21' Example 23 A crotyl-terminated polyurethane whichcontains two Following the procedure of Example 3, and using reactivedouble bonds per average molecule in a near necessary reactants, apolyene of the following formula terminal position was preparedfollowing the general prowas prepared:

cedure of Example 3. The resulting polymeric polyene was found to havethe following formula:

Examples 24-42 Following the general procedure of the prior examples,

Example 22 and using the necessary reactants, a series of polyeneshaving the formula: Following the procedure of Example 3, and using 55necessary reactants, a polyene of the following formula l was prepared:A

27 Example 50 0.005 mole of the allyl-terminated liquid Prepolymer F wascharged to a 2 oz. glass jar along with a stoichiometric amount to reactwith the allyl groups of the prepolymer, i.e., 0.0033 mole oftrimethylolpropane tris (p-mercaptopropionate) having a molecular weightof 398. The liquid reactants were stirred together for V2 hour at 140 C.Thereafter the reactants were cured under ambient conditions. After 2days the liquid reactants began curing and at the end of a 2 weekperiod, a solid, odorless, self-supporting, cured elastomericpolythioether polymer resulted.

The following examples show the curing reaction of the instant inventionas catalyzed by a peroxide. In all the examples g. of theallyl-terminated liquid polyene prepolymer were admixed in a 2 oz. glassjar with a stoichiometric amount of a polythiol, i.e. pentaerythrioltetrakis (fi-mercaptopropionate) sufiicient to react with all the allylgroups on the prepolymer. In addition, the peroxide was added along withan accelerator for the peroxide. The reactants were briefly stirred andthen left to cure indoors at ambient conditions. The results follow:

28 120 C. Excess allyl alcohol was stripped by vacuum at 115 C. for 23hours. The thus-formed CH =CH terminated polyene prepolymer had amolecular weight of approximately 2460-2500, and a viscosity of 16,000cps. as measured on a Brookfield viscometer at 30 C. 0.005 mole of thethus-formed polyene and 0.005 mole of trimethylolpropane triallyl etherwere charged to a 2 oz. jar along with a stoichiometric amount of thepolymeric dithiol prepared in Example 66. After adding 0.063 gram ofbenzoyl peroxide and 0.15 gram of dimethylaniline, the mixture in the'glass jar was immediately stirred. Thereafter the mixture was pouredinto a plastic mold for curing. Within 30 minutes a solid,self-supporting, odorless, cured elastic polymer resulted.

Example 61 4.5 grams (0.02 mole) diallyl adipate were charged to a 2 oz.glass bottle along with a stoichiometric amount of a polythiol to reactwith the CH;=CH- groups in the diallyl adipate, i.e., 4.9 g. (0.01 mole)of pentaerythritol tetrakis (B-mercaptopropionate), 0.05 g. of lauroylperoxide and 0.15 g. dimethylaniline. The reactants were Curingobservations Example Polyene No. prepolymer Peroxide (g.) Accelerator(g).

0.1 g. benzoyl per- 0.2 g. dimethyl anioxide. line. 0.4g.of69%cumene 0.1g. cobalt naphhydroperoxide. thanate 0.1 g. cyclohexanone 0.2 g. dimethyl aniperoxide. line and 0.01 g. co-

halt naphthanate.

Cured instantly while mising. Cured to a solid in 7 days.

stirred briefly and then placed on the bench top at ambient conditions.A self-supporting, solid, odorless, cured polythioether polymer resultedin less than 15 minutes.

Example 62 Example 61 was repeated except that 0.02 mole of diallylphthalate was substituted for the diallyl adipate. A selfsupporting,solid, odorless, cured polythioether polymer product resulted in lessthan 30 minutes.

Example Pre- Poly- No. polymer Filler (g.) thiol Curing observations54.. I 8.0 g. Emtal Talc A Cured to an odorless solid in 4 hrsr. I 8.0g. Unimal 303 DO. I 8.0 g. Desertalc 132 A Cured to an odorless solid in24 hrs. I 3.0 g. HiSil 233 A Cured to an odorless solid in 1% hours. 1:.-(10 None N0 cure after 30 days. I 3.0 g. HiSil plus 5 g. T102..." A.-Cured to an odorless solid in 4 hrs.

1 A=pentaerythritol tetrakis (fl-mereaptopropionate) Z A talecommercially available from Eastern Magnesia Talc 00., Burlington, Vt. 8Polyaluminum silicate manufactured by United Clay Mines, Trenton, NJ.ognltin acicular platey talc commercially available from Desert MineralsInc., Los Angeles l Areinforcing silica commercially available fromColumbia Southern Chemical Corp.

Example 1510 g. of a commercially available poly(oxypropylene) glycolsold under the trade name Pluracol P 2010" by Wyandotte Chemical Corp.was charged to a resin kettle maintained under a nitrogen atmosphere andequipped with a condenser, stirrer, thermometer and gas inlet andoutlet. The reactant was degassed at room temperature for 3 hours. 265.4g. of an 80-20% isomer mixture of tolylene-2,4-diisocyanate andtolylene-2,6-diisocyanate respectively sold under the trade name MondurTD 80 was charged to the kettle and the kettle was heated for 2 hours at120 C. with stirring under nitrogen. Thereafter, 116.9 g. (2 moles) ofallyl alcohol was added to the kettle and the mixture was refluxed for16 hours at Example 63 Example 61 was repeated except that 0.02 mole ofdiallyl succinate was substituted for the diallyl adipate. Aself-supporting, solid, odorless, cured polythioether product resultedin 30 minutes.

Example 64 Example 61 was repeated except that 0.02 mole of 2,2-diallyloxypropane was substituted for the diallyl adipate. Aself-supporting, solid, odorless, cured polythioether polymer productresulted in less than 15 minutes.

Example 65 1.9 grams (0.02 mole) of diallyl amine were charged to a 202. glass bottle along with a stoichiometric amount of polythiol toreact with the vinyl groups in the diallyl amine, i.e., 4.9 g. (0.01mole) of pentaerythritol tetrakis (p-mercaptopropionate), 0.04 g.benzoyl peroxide and 0.1 g. dimethylaniline. The reactants were stirredbriefly. In less than minutes a self-supporting, solid, odorless, cured,clear, rubbery polythioether polymer resulted.

The following shows another example of the curing of a polymericthiol-containing compound and a vinyl-terminated polymer.

Example 66 1.5 moles of B-mercaptopropionic acid, 0.5 mole of acommercially available poly (propylene ether) glycol sold under thetradename Pluracol P-2010 by Wyandotte Chemical Corp. and 0.1 g.p-toluenesulfonic acid and 50 ml. benzene were charged to a resin kettlemaintained under a nitrogen atmosphere and equipped with a condenser,stirrer, thermometer and gas inlet and outlet. The mixture was heatedand the benzene-water azeotrope was collected. The actual amount ofwater collected amounted to 17.5 g. The reaction was vacuum-stripped forseveral hours at 70 C. to remove benzene. The resulting polythiolpolymer had a molecular weight of about 2210-2230 and an averagefunctionality of 2 and was collected for use herein.

659 g. (0.145 mole) of a poly(propylene ether) triol commerciallyavailable from Wyandotte Chemical Corp. under the tradename Pluracol TPE4542 having a molecular weight of about 4500 and a hydroxyl number of37.1, and 0.3 g. of dibutyl tin dilaurate were charged to a resin kettlemaintained under a nitrogen atmosphere and equipped with a condenser,stirrer, thermometer and gas inlet and outlet. The reactants weremaintained at 110 C. for 1 hour and then cooled under nitrogen to roomtemperature. 25.2 g. (0.435 mole) of allyl alcohol was added to thekettle followed by 75.7 g. (0.435 mole) of an 8020% isomer mixture oftolylene-2,4-diisocyanate and tolylene 2,6-diisocyanate respectivelysold under the tradename Mondur TD 80. The temperature reached 55 C. in6 minutes. A sample was titrated for NCO resulting in 6.02 mg. NCO/g.after minutes. After 1 hour the NCO titration showed 0.997 mg. NCO/ g.The polyene polymer had a molecular weight of about 5200 and an averagefunctionality of 3 and was vacuum stripped at 70 C. for 1 hour and thencollected. 0.003 mole of the polythiol polymeric material formed suprawas charged to a 2 oz. glass jar along with 0.002 mole of theallyl-terminated polyene polymer formed herein, 0.10 g. benzoyl peroxideand 0.20 g. dimethylaniline. The reactants were stirred briefly. In lessthan /2 hour a self-supporting, solid, odorless, clear, curedpolythioether polymer product resulted.

Example 67 3 grams of a linear saturated hydrocarbon backboneethylene/propylene/nonconjugated diene terpolymer commercially availableunder the trade name Nordel by E. I. du Pont de Nemours & Co., which hasbeen visbroken until it had a reduced specific viscosity of 0.99 andcontained 0.4 vinyl, 6.4 trans and 0.4 vinylidene unsaturated groups per1000 carbon atoms, were dissolved in 100 ml. of benzene in a glass jar.A 50% excess over the stoichiometric amount, i.e., 0.0006 mole (0.3 g.)of pentaerythritol tetrakis (fl-mercaptopropionate) was added to the jarin addition to 0.015 g. benzoyl peroxide and 0.03 g. dimethylaniline.The glass jar was set aside under ambient conditions. After 24 hours thebenzene had substantially evaporated leaving a gelatinous polymericprecipitate. Acetone was added to precipitate more polymer. The polymerwas filtered off, washed with acetone and dried in a vacuum oven at 60C.

2.3 grams of the above polythioether polymer product was extracted withbenzene along with a control sample of the starting visbroken Nordelmaterial. The contro sample showed a nil gel content (benzene insoluble)whereas the peroxide cured (crosslinked) solid polythio ether polymerproduct had a gel content in excess of 50%.

30 Example 68 643 grams (0.32 mole) of a commercially availablepoly(propylene ether) glycol sold under the trade name Pluracol P 2010by Wyandotte Chemical Co. were degassed at room temperature for 1 hourand then charged to a resin kettle maintained under a nitrogenatmosphere and equipped with a condenser, stirrer, thermometer and gasinlet and outlet. 111.4 grams (0.64 mole) of an 20% isomer mixture oftolylene-2,4-diisocyanate and tolylene-2,fi-diisocyanate, respectively,solid under the trade name Mondur TD 80, were added to the kettle. After45 minutes, the temperature was raised to 120 C. and the reaction wascontinued for 50 minutes. A sample was removed and titrated for NCO,resulting in 33.54 mg. NCO/g. 62.7 grams of diallyl amine were added at105 C. and the reaction was continued for 10 minutes. A sample wastitrated resulting in an NCO content of 1.20 mg. NCO/g. A vacuum wasapplied to the kettle for 1 hour at C. followed by cooling undernitrogen. The resulting product had a molecular weight of about 2540- 2580 and an ene functionality of 4.

10 grams of the thus-formed polymer were charged to a 2 oz. glass jaralong with 2 g. of pentaerythritol tetrakis- (fl-mercaptopropionate) and0.06 g. azo'bisisovaleronitrile. The liquid reactants were brieflystirred together and set aside under ambient conditions. Within 30minutes a solid, adorless, elastomeric, cured polythioether product wasobtained.

Example 69 215 grams of poly(ethylene imine) commercially available fromDow Chemical Co. under the trade name Montrek 18" along with 41.5 g.allyl isocyanate were charged to a resin kettle maintained under anitrogen atmosphere and equipped with a condenser, stirrer, thermometerand gas inlet and outlet. The reactants were maintained at 70 to 80 C.during addition. The reaction was continued for 1 hour at 70 C.

10 grams of the thus-formed polymer were charged to a 2 oz. glass jaralong with 1.5 g. of pentaerythritol tetrakis( s-mercaptopropionate) and0.25 g. of azobisisobutyronitrile. The mixture was briefly stirred andplaced in a warm room at about 120 F. Within 2 hours a solid,self-supporting, odorless, cured polymer product was formed.

Example 70 The polymeric polythiol (0.003 mole, f=2) from Example 66 wasadmixed with a stoichiometric amount (0.002 mole, i=3) of a monomericpolyene, glycerol trioleate (triolein, molecular weight 885), 0.05 g.benzoyl peroxide and 0.10 g. dimethylaniline. The jar containing thereactants after mixing was set aside under ambient conditions. Within /2hour the liquid mixture was converted to a self-supporting, solid,odorless, clear, rubbery, cured polythioether product.

The following example shows the operability of the instant inventionwhen the polyene contains acetylenic linkages.

Example 71 400 grams (0.20 mole) of a commercially available liquidpolymeric diisocyanate sold under the trade name Adiprene L- by E. I. duPont de Nemours & Co. were charged to a dry resin kettle maintainedunder a nitrogen atomsphere and equipped with a condenser, stirrer,thermometer and gas inlet and outlet. 25.2 grams (0.45 mole) ofpropargyl alcohol were charged to the kettle and the reaction wascontinued for 17 hours with stirring at 100 C. Thereafter the nitrogenatmosphere was removed and the kettle was evacuated 15 hours at 100 C.

10 grams of the propargyl terminated liquid prepolymer, 3.0 grams ofpentaerythritol tetrakis (/3mercaptopropionate), 0.06 gram of benzoylperoxide and 0.15 gram of dimethylaniline were admixed in a 2 oz. glassjar, stirred briefly and set aside under ambient conditions.

Within /2 hour a solid, odorless, self-supporting, cured, elastomericpolymer product resulted.

The following example shows the necessity of having a free radicalgenerator present, e.g., oxygen, in order to cure by the instantinvention.

Example 72 40 grams of Prepolymer I and 10 grams of a filler soldcommercially under the trade name Hi Sil 23 3 by Columbia SouthernChemical Corp. were charged under nitrogen to a 200 ml. round bottom3-necked flask maintained under a nitrogen atmosphere and mixedthoroughly. The flask was heated by a water bath to 60 C. under fullvacuum for 2 hours. The flask was then allowed to cool under vacuum. 4grams of pentaerythritol tetrakism-mercaptopropionate) were charged tothe flask under nitrogen and and the reaction was stirred continuousy.After 6 days under nitrogen, no cure was noted. The reaction was thenexposed to oxygen from the atmosphere and a solid, cured, odorless,elastomeric product resulted within 45 minutes.

Example 73 125 g. of Prepolymer E from Example herein was charged to aErlenmeyer flask equipped with a magnetic stirrer and connected bytubing to another Erlenmeyer flask containing 54 g. oftrimethylolpropane tris([3-mercaptopropionate). The system was evacuated(0.05 mm.) while heating the polymer to 100 C. with stirring. After 2hours all bubbling ceased. An additional /2 hour evacuation wasperformed. Thereafter the trimethylolpropane tris(/3-mercaptopropionate)was poured into the flask containing Prepolymer E under nitrogen. Afterstirring to insure good mixing, heat was removed and the reaction wascontinued under nitrogen for 4 days. No curing was observed. A sample ofthe unreacted material was removed from the Erlenmeyer flask undernitrogen and placed in a 2 oz. jar. The sample was exposed to ambientconditions indoors and in about 40 minutes evidence of curing (viscositychange) was observed. Within 8 hours, an odorless, solid, elastomeric,cured polymer product was obtained.

The following example shows the ability to retard the curing process ofthe instant invention by the use of antioxidants.

Example 74' 10 g. of Prepolymer E from Example 5 was added to each ofthree 2 oz. jars. To one of the jars was added 3 ml. of benzenecontaining 0.5% based on the weight of the prepolymer of an antioxidantsold under the trade name Santonox commercially available from MonsantoChemical Co. To another of the jars containing Prepolymer E was added 3ml. of benzene containing 0.5 based on the weight of the prepolymer ofan antioxidant sold under the trade name Dalpac FG commerciallyavailable from Hercules Powder Co. To the third jar was added 3 ml. ofbenzene as a control. To blend the components the jars were heated in aforced draft oven set at 150 C. for 25 minutes with frequent stirring.The jars were withdrawn from the oven and 1.3 g. of trimethylolpropanetris (fl-mercaptopropionate) was added to each of the jars and curingwas initiated indoors under ambient conditions. The control run, withoutany antioxidant present, cured within A: hour to a solid elastomericpolymer product. The example containing Dalpac FG cured to a solidpolymer product after 12 days whereas the sample containing Santonoxrequired more than 2 weeks before a solid self-supporting, curedpolymeric product resulted.

The polyenes used in the instant invention may be used as blends ormixtures of monoenes or polyenes having the same or differentfunctionalities so long as the average functionality of the blend ormixture is at least 2. Similarly, the polythiols used herein may be usedas blends or mixtures of monothiols or polythiols having the same ordifferent functionalities as long as the average functionality of theblend or mixture is at least 2.

The polyene/polythiol mole ratio is selected so as to provide a solidfinal cured product, i.e., one that is nonflowing and structurallyself-supporting under ambient conditions In typical cases, as shown bythe examples, this ratio can be about 0.2 to 5 moles thiol groups permole ene groups. In general the mole ratios significantly above or belowI tend to give a high proportion of chain extension or grafting whereasmole ratios near 1 give predominantly chain extension and cro-sslinking.Occasionally, however, ratios necessary to give a solid as aforesaid maylie outside the stated range, and experimentation may be necessary todetermine a suitable ratio to give a solid. This experimentation iseasily carried out, and offers no difliculties to those skilled in theart. Examples 80 and 8186 show how to vary the ratio and how one canempirically determine the amount of polythiol necessary to react withthe polyene to obtain a solid, self-supporting, cured polymeric product.

Examples 75-80 show the ability to use mixtures of the polythiols andhow to empirically determine the amount of polythiol necessary to formcured, solid, selfsupporting polymeric products by the instantinvention.

As shown in Examples 75-80, 30 grams of Prepolymer I from Example 8 wereadmixed with varying ratios of a mixture of polythiols and cured in thepresence of a peroxide with dimethylaniline as a peroxide activator.

In Examples 81-86, 30 grams of Prepolymer I from Example 8 were admixedwith varying amounts of a polythiol, i.e., pentaerythritol tetrakisB-mercaptopropionate) along with 1.5 g. of 10% benzoyl peroxide (inbenzene) and 0.3 g. of dimethylaniline. The mixture was briefly stirredin a 2 oz. glass jar and then transferred to a shallow aluminum foildish. The mixtures were then allowed to cure indoors under ambientconditions. The results of the amount of reactants necessary for aselfsupporting polymeric structure are shown.

EXAMPLE S 75-80 10% solution Polythiol mixture in benzene of benzoylDimethyl Curing Self- Example Polyene Q-43 1 13,-23 3 peroxid anilinetime Shore A supporting N o. polymer (g.) (g.) (g.) (g.) (minutes)Hardness structure 75 I 2. 0 1.5 0.3 3 23 Yes. I 2.3 0.6 1.5 0.3 6 13Yes. I 1.7 1.2 1.5 0.3 7 0 Yes. I 1.2 1.7 1.5 0.3 9 0 Yes. I 0.6 2.3 1.50.3 N0. I 0 2.9 1.5 0.3 N0.

1 Polyene Prepolymer I from Example 8. x 2 Q,-43=pentaerythritoltetrakis(fl-mercaptopropionate) commercially available from CarlisleChemical Co. 8 E-23=ethylene glycol bis(fl-mereaptopropionate).

4 No cure.

EXAMPLES 81-86 Product properties 10% Polythiol benzoyl Dimetliyl Seli-Polyene Q-43 1 peroxide aniline Curing time Shore A supporting ExampleNo. polymer (g.) (g.) (g.) (minutes) Hardness structure 1. 7 l 5 1.5 1.5 1.2 l. 5 0.9 1.5 0. 6 l 5 0. 1.5

1 30 g. polyene Prepolymer I from Example 8. 2 Q43=pentaerythritoltetrakis(fi-mercaptopropionate) commercially available from CarlisleChemical 00.

Example 87 Example 91 The following formulations were made up:

Formula- Formulation No. I tlon No. II Ingredients (parts) (parts)Prepolymer D from Example 4 100 100 'IiOz (pigment) 4 4 Unirnal 507(kaolin clay) 60 85 Unirnal 303 (kaolin clay). 25 Thickening agent (76%si bestos fibers) 4 4 Pentaerythritol tetrakis (B-mercaptopropionate) 1010 The above formulations were briefly admixed for homogeneity andthereafter air cured indoors. Formulation I cured in approximately 6hours to an elastomeric sealant whereas Formulation II cured in two daysto an elastomeric sealant.

Example 88 Example 89 50 grams of Prepolymer H along with 5.0 g. ofpentaerythritol tetrakis(;8 mercaptopropionate), 2.5 g. of a 10% benzoylperoxide in benzene and 0.5 g. N,N-di methylaniline were stirredtogether briefly in a glass jar and then poured into an aluminum mold inthe shape of a shallow dish. The mold was allowed to set for hours afterwhich time the mold was torn away from the molded article which set to asolid in the exact shape of the mold.

Example 90 0.005 mole of Prepolymer E from Example 5 was charged to a 202. glass jar along with 0.0033 mole of trimethylolpropane tris(fimeroaptopropionate), 0.2 g. benzoyl peroxide and 0.5 g. dimethylaniline.The reactants were stirred briefly and then coated onto a piece of 17pt. clay coated paper by means of a No. rod. The paper was then setaside at ambient conditions. After 10 minutes a clear, solid coatingresulted on the paper. The same technique was used successfully to coatcellophane, aluminum foil, steel plate stock, Mylar polyester film,plywood, and a concrete block of the type used in building construction.

20 grams of the polymeric product from Example 10 was mixed in analuminum dish with 2.2 g. of pentaerythritol tetrakis(/3mercaptopropionate) commercially available from Carlisle Chemical Co.under the trade name Q-43, 0.10 g. benzoyl peroxide and 0.2 g.dimethylaniline. The sample cured to a tack-free solid which had a colorof less than 1 on the Gardner Scale. After exposure in a Fadeometer for50 hours, the color increased to a value of 4 on the Gardner Scale.

A similar polymer prepared from PPG-2025, tolylene 2,4 diisocyanate andallyl alcohol, cured with pentaerythritol tetrakis(,8mercaptopropionate) and acetophenone by irradiation with ultravioletlight also had a Gardner color of less than 1. However, after 50 hoursin the Fadeometer the Gardner color rose to 13.

Example 92 5.2 grams of decaglycerol dioleate (Drew Chemical Corp.) and2.0 grams of ethylene glycol bisQB-mercaptopropionate) were dissolved inethanol in an aluminum tray. 0.04 gram of benzoyl peroxide and 0.1 gramdimethylaniline were added to the mixture and the mixture was set asideunder ambient conditions. After 3 days the product had not solidified toa crosslinked network.

Example 93 94.5 grams of dimer acid commercially available from EmeryIndustries, Inc., under the trade name Empol 1010 and 103.5 grams ofallyl alcohol were admixed in benzene in a Z-neck flask. The reactionwas heated gently for 19 hours at C. at which time it was determined bytitration that less than 6% of the carboxyl group content was unreacted.The reaction was discontinued and the reactants were washed with water.The thus-formed emulsion was salted out thoroughly, the benzene layerwas separated and dried to remove residual moisture. The benzene 'wasdistilled off in vacuum to obtain the diallyl ester of dimer acid.

The diallyl ester of the dimer acid product (30 grams) was admixed withQ-43 in a 1:1 mole ratio along with 0.15 gram benzoyl peroxide and 0.3gram dimethylaniline in an aluminum tray. After 30 minutes a cured solidproduct resulted.

The curing example was repeated except that the mole ratio of thediallyl ester of dimer acid to Q-43 was 2: 1. The cured product washarder than the product obtained under the 1:1 mole ratio of diallylester to Q-43.

14 grams of dimer acid, 6 grams of pentaerythritoltetrakis(fi-mercaptopropionate), 0.07 gram. benzoyl peroxide and 0.15gram dimethylaniline were mixed in an aluminum tray. The mixture was setaside under ambient conditions. After 22 hours the product had notsolidified to a cross-linked network.

EXAMPLES 94-111 Chemical free radical Sample No. Polyene Source ofpolyene generating reagent 1 Polythiol 2 94 1,2,4-trivinylcyclohexaneAldrich Chemical Co., Inc Benzoyl peroxide 01-43 95.... 1,5-hexadiene dodo Q43 96.-.- Diallyl terephthalate Chemicals Procurement Lab, Inc 97.".Diallyl oxalate Monomer-Polymer Labs, Inc 98.- Diallyl1,4cyclohexanedicarboxylate .do

Tetraallyl orthosilicate Diallyl phenyl phospliite Aldrich Chemical Co.,Inc. Chemicals Procurement La Aldrich Chemical 00., Inc. K. & K.Laboratories, Inc. N,N-d.iallylformamide Aldrich Chemical 00., Inc

104 NaN,N ,N-tetraallylmethylene- Monomer-Polymer Labs, Inc do iamine.105 Triallyl cyanurate Aldrich Chemical 00., Inc do P-43 1064-vinyl-1-cyclohexene K. & K. Laboratories, Inc 107 Dicthylcneglycoldivinyl ether (.0 (Polyscicnces, Inc

mole), diallyl amine (.1 mole). {Monomer-Polymer Labs, Inc. Triallylphosphate Aldrich Chemical (30., Inc do P-43 Diallyl carbonate ChemicalsProcurement Lab. Inc

N N-diallyl piperazin do Allyl dicyclo carbonate (DR-30 from PP G Ind.Inc..-

1 Concentration of dimethylaniline curing rate accelerator varied from1.0 to 3.0 parts/100 parts curable composition; benzoyl peroxide reagentconcentration was 0.2 to 0.5 part/100 parts of curable composition. Curethrough times ranged from 3 minutes to minutes.

Q,43 is pentaerythritol tetrakis (B-mercaptopropionato; P-33 istrimothylolpropanc tris (,3-n1crcaptopropionate). The polythiol is usedin the theoretical equivalent amount based on the polyene used.

Examples 112-120 Example 65 was repeated except that the .02 mole of ofdiallyl amine was replaced by 0.02 mole of the polyenes from Examples24, 25, 27, 28, 30, 31, 32, 39 and 40, respectively. In each instance asolid cured product was obtained in less than minutes after mixing wascompleted.

Example 121 916 grams (0.46 mole) of a commercially available liquidpolymeric diisocyanate sold under the trade name Adiprene L100 by E. I.du Pont de Nemours & Co. were charged to a dry flask maintained under anitrogen atmosphere and equipped with a condenser, stirrer, thermometerand gas inlet and outlet. 197 grams (0.92 mole) of the diallyl ether oftrimethylolpropane were charged to the vessel along with 0.56 g. dibutyltin dilaurate catalyst. The flask and contents were heated with stirringfor minutes at 50 C. to yield a polytetraene of about 2400 M.W.

To the tetraene were added 230 grams pentaerythritol tetrakis(fi-mercaptopropionate), 1.2 grams dilaurylthiodipropionate, 136 gramsof dioctyl phthlate, 1.2 grams Plastanox 2246 (hindered phenolantioxidant sold by American Cyanamid Co.), 6.7 grams benzoyl peroxideand 14 grams dimethylaniline. An aliquot of this chemically curableliquid composition was cast on a glass plate in a layer 40 mils thick.The layer skin cured to a solid through the entire thickness in lessthan 3 minutes, or at a liquid-to-solid conversion rate of over 13mils/minute. The solid rubbery product had a Shore A hardness of 60, atensile strength of 150 p.s.i. and an elongation at failure of 25percent.

Example 122 An 80/20 mixture of tolylene 2,4-diisocyanate and tolylene2,6-diisocyanate (1 mole) was reacted with allyl alcohol (2 moles) underthe conditions used for the similar synthesis described in Example 116.The resulting diene (3 moles) was mixed with 2.1 moles of the tris(3-mercaptopropyl) ether of tris(2 hydroxyethyl) isocyanurate, 0.5 partbenzoyl peroxide and 1.0 part dimethylaniline per 100 parts of curablecomposition.

100 grams of the above curable composition were placed in a layer 500mils deep in a small aluminum mold and set aside at ambient conditions.After 5 minutes the liquid composition was cured to a crosslinked solidhaving a Shore A hardness greater than 20. The conversion from liquid tosolid occurred at a rate of over 100 mils/ minute.

The solid cured polythioether polymer products resulting from theinstant invention have many and varied uses. Examples of some usesinclude but are not limited to adhesives; caulks; elastomeric sealants;coatings, en-

capsulating or potting compounds; liquid castable elastomers; thermosetresins; impregnants for fabric, cloth, fibrous webs and other poroussubstrates; laminating adhesives and coatings; mastics; glazingcompounds; fiberglass reinforced composites; sizing or surface finishingagents; filleting compounds; cure in place gasketing compounds; rocketfuel binders; foamable thermosetting resins or elastomers; moldedarticles such as gaskets, diaphragms, balloons, automobile tires, etc.

The molecular weight of the polyenes of the present invention may bemeasured by various conventional methods, including solution viscosity,osmotic pressure and gel permeation chromatography. Additionally, themolecular weight may be calculated from the known molecular weight ofthe reactants.

The viscosity of the polyenes and polythiols may be measured on aBrookfield Viscometer at 30 or 70 C. in accord with the instructionstherefor.

The components to be cured may be prepared as either single-packaged ormulti-packaged liquid polymer systems which may be cured to solidpolythioether elastomers without liberating gaseous by-products whichcause bubbles and voids in the vulcanizate. Thus, there is providedcurable liquid polymer systems composed of polyenes and polythiols inwhich the components individually are storage stable and which are notsensitive to or deteriorated by traces of moisture or oxygen containinggas such as may be encountered during normal storage or handlingprocedures. Solid resinous or elastomeric products may be prepared fromflowable liquids in a system in which the rate of curing may beinhibited or retarded by the use of chemical inhibitors, antioxidants,inert atmospheres and the like. The cured product may be characterizedas in the thermally and oxidatively stable state since there is noreactive carbon-to-carbon unsaturation in the main backbone chain.

As used herein the term polyene and the term polyne refers to single orcomplex species of alkenes or alkynes having a multiplicity of terminalreactive carbon-to-carbon unsaturated functional groups per averagemolecule. For example, a diene is a polyene that has two reactivecarbon-to-carbon double bonds per average molecule, while a diyne is apolyyne that contains in its structure two reactive carbon-to-carbontriple bonds per average molecule. Combinations of reactive double bondsand reactive triple bonds within the same molecule are also possiblesuch as for monovinylacetylenc which is a polyeneyne under thisdefinition. For purposes of brevity all these classes of compounds arereferred to hereafter as polyenes.

In defining the position of the reactive functional carbon-to-carbonunsaturation, the term terminal is intended to mean that functionalunsaturation is at an end of the main chain in the molecule; whereas bynear terminal is intended to mean that the functional unsaturation isnot more than carbon atoms and typically less than 8 carbon atoms froman end of the main chain in the molecule. The term pendant means thatthe reactive carbonto-carbon unsaturation is located terminal ornearterminal in a branch of the main chain as contrasted to a positionat or near the ends of the main chain. For purposes of brevity all ofthese positions are referred to herein generally as terminalunsaturation.

Functionality as used herein refers to the average number of ene orthiol groups per molecule in the polyene or polythiol, respectively. Forexample a triene is a polyene with an average of three reactivecarbon-to-carbon unsaturated groups per molecule and thus has afunctionality (f) of three. A dithiol is a polythiol with an average oftwo thiol groups per molecule and thus has a functionality (f) of two.

It is to be understood that the functionality of the polyene and thepolythiol component is commonly expressed in whole numbers although inpractice the actual functionality may be fractional. For example, apolyene component having a nominal functionality of 2 (from theoreticalconsiderations alone) may in fact have an effective functionality ofsomewhat less than 2. In an attempted synthesis of a diene from a glycolin which the reaction proceeds to 100% of the theoretical value forcomplete reaction, the functionality (assuming 100% pure startingmaterials) would be 2.0. If however, the reaction were carried to only90% of theory for complete reaction, about 10% of the molecules presentwould have only one ene functional group, and there may be a trace ofmaterial that would have no ene functional groups at all. Approximately90% of the molecules, however, would have the desired diene structureand the product as a whole then would have an actual functionality of1.9. Such a product is useful in the instant invention and is referredto herein as having a functionality of 2.

The term reactive unsaturated carbon-to-carbon groups means groups whichwill react under proper conditions as set forth herein with thiol groupsto yield the thioether linkage as contrasted to the term unreactivecarbon-to-carbon unsaturation which means groups found in aromaticnucleii (cyclic structures exemplified by benzene, pyridiene,anthracene, and the like) which do not under the same conditions reactwith thiols to give thioether linkages.

Highly water-sensitive groups are intended to include, for example,isocyanate, acylhalide such as acylchloride, anhydride and the likewhich readily react with water, alcohols, ammonia, amines and the like.

Odorless has been used herein to mean the substantial absence of thewell-known offensive and sometimes obnoxious odors that arecharacteristic of hydrogen sultide and the derivative family ofcompounds known as mercaptans.

The term non-yellowing means the substantial resistance during prolongedexposure to actinic radiation such as exposure in sunlight, to unsightlyor uncontrollable discoloration.

It is understood that the foregoing detailed description is given merelyby way of illustration and that many variations may be made thereinwithout departing from the spirit of this invention.

What is claimed is:

1. A chemically curable composition useful for obtaining an essentiallyodorless, solid polythioether, said curable composition consistingessentially of:

38 (A) a terminally unsaturated polyene component which comprises theformula wherein m. is an integer of at least 2, wherein X is R R liltzaii. l i R where f is an integer from 1 to 9; R is a radical selected fromthe group consisting of hydrogen, fluorine, chlorine, furyl, thienyl,pyridyl, phenyl and substituted phenyl, benzyl and substituted benzyl,alkyl and substituted alkyl, alkoxy and substituted alkoxy, cycloalkyland substituted cycloalkyl; said substituents on said substitutedmembers selected from the group consisting of nitro, chloro, fluoro,acetoxy, acetamide, phenyl, benzyl, alkyl, alkoxy and cycloalkyl; saidalkyl and alkoxy having from 1 to 9 carbon atoms and said cycloalkylhaving from 3 to 8 carbon atoms; wherein (A) is free of reactivecarbon-to-carbon unsaturation; free of highly water-sensitive members;and is a polyvalent chemically compatible member of the group consistingof carbonate, carboxylate, carbonyl, ether, silane, silicate,phosphonate, phosphite, phosphate, alkyl and substituted alkyl,cycloalkyl and substitute cycloalkyl, aryl and substituted aryl,urethane and substituted urethane, urea and substituted urea, amine andsubstituted amine, amide and substituted amide, hydroxyl, heterocycliccarbon containing radical, and mixtures thereof; said substituents onsaid members being defined above, said component having a molecularweight in the range from about 64 to 20,000; and a viscosity in therange from essentially 0 to 20 million centipoises at C.; (B) apolythiol component having a molecular weight in the range from about 50to about 20,000 of the general formula:

R -fSH wherein R is a polyvalent organic moiety free from reactivecarbon-to-carbon unsaturation and n is at least 2, the sum of m and nbeing greater than 4, with the ene/thiol mole ratio being selected so asto provide a cross-linked solid, self-supporting cured product; and

(C) a chemical free radical generating reagent.

2. The composition of claim 1 wherein (A) has the n it wherein a and bare integers greater than 1;

R ilskalmember of the group consisting of hydrogen and R is a member ofthe group consisting of hydrogen, and

saturated alkyl;

R, is a divalent derivative of the group consisting of phenyl, benzyl,alkyl, cycloalkyl, substituted phenyl, substituted benzyl, substitutedalkyl and substituted cycloalkyl,

said alkyl, cycloalkyl and substituents on members substituted beingdefined as in claim 1.

39 40 3. The composition of claim 1 wherein the polyene has the formula:

0 I" 0 O' (I) CHg=CH-CH1 N -OCH CHz-0iCH o-oH2oH,-ooN oH2 A 1 L A J I R1R1 CH (EH2 u wherein n is at least 1; and 10 R is a member of the groupconsisting of CHZZCHfiCHf) 5. The composition of claim 1 wherein thepolyene hydrogen, phenyl, cycloalkyl and alkyl; has the formula:

UH; CH3 [E r/ I rrvl E/\ NH GH 0 GNH NH-(J-0CH 0- NH NH- -O-OH GH=CH lL\ 4 |u JL\ Jn Z IIIH P 0 6 2) said substituent on member which issubstituted, the where n is at least 1. cycloalkyl, and the alkyldefined as in claim 1.

4. The composition of claim 1 wherein the polyene has the formula:

CH3 at. r R t 0 CH;=CHLOHQ\ N-o-ooHzoH,ot J oH,)- i-0oH2oH,od-NH NH-i-oCHzoH,-

\ A l L 4 J J i E E OCCH OOH CH-O -NoH CH=CH L /6 2 2 Ju l /1: 2

R1 wherein n is at least 1; and R is a member of the group consisting ofCHZzCHaCHZ'h 6. The composition of claim 1 wherein the polyene hashydrogen, phenyl, cycloalkyl and alkyl; 50 the formula:

said substituent on member which is substituted, the cyclowherein thesum of x+y+z is at least 1; n is at least 1, alkyl, and the alkyldefined as in claim 1. and P is at least 2.

7. The composition of claim 1 wherein the polyene has the formula:

